A152178 Smallest prime factor of G-n, where G is any sufficiently large power tower of 3, e.g., Graham's number.

3, 2, 5, 2, 107, 2, 3, 2, 101, 2, 29, 2, 3, 2, 13, 2, 3626257, 2, 3, 2, 7, 2, 5, 2, 3, 2, 1511, 2, 173, 2, 3, 2, 5, 2, 7, 2, 3, 2, 197, 2, 13, 2, 3, 2, 17491, 2, 18540593, 2, 3, 2, 53, 2, 5, 2, 3, 2, 19, 2, 17, 2, 3, 2, 5, 2, 11, 2, 3, 2, 29, 2, 97, 2, 3, 2, 251

Offset

0,1

Comments

Least prime p such that A240162(p) == n (mod p). - Jinyuan Wang, Aug 30 2020

Links

Jinyuan Wang, Table of n, a(n) for n = 0..100

Wikipedia, Graham's number

Example

a(2) = 5 because 3^3^3^... - 2 = 0 (mod 5).

Crossrefs

Cf. A152177, A240162.

Sequence in context: A319044 A230820 A324549 * A274164 A103340 A106615

Adjacent sequences: A152175 A152176 A152177 * A152179 A152180 A152181

Keyword

nonn

Author

Karl W. Heuer, Nov 28 2008

Status

approved